Double-curved shell

Abstract

Triangulated shells can be free-formed but are uneconomical compared to translational shells that can only be flat. Scale-trans shells are limited in terms of number and arrangement of the openings. The present invention provides a free-formed, custom-tailored shell surface and a regularly shaped, mass-produced shell surface that can be assembled fairly evenly from advantageously quadrangular mesh elements having coplanar node points. The flexibility of a triangle net of shell pieces in a large scale is combined with the evenness of a quad net for meshes in a small scale, whereby triangular meshes at the shared side of adjoining square nets are combined in pairs to give irregular quadrangular meshes having coplanar vertices. The inventive shell is especially suitable for use as an energy-saving building such as a weekend home, emergency shelter, cupola of an observatory, roof of a building or an inner courtyard, as the shell of a large multi-story building or as a sports hall or factory building. It is also suitable as a part of a vault, and as a complex shell consisting of a single continuous surface for exhibition or station buildings. Parts of a Bohemian dome, cushion-roof, Isler shell or blob can be combined within any individual shell.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a double-curved shell, in particular in the field of building construction. Such a shell is prefabricated of structural elements, it is custom-tailored or mass-produced. It can be purely synclastic, purely anticlastic, or mixed-curved (synclastic=curved toward the same side in all directions=in a Gaussian sense positively curved; anticlastic=having opposite curvatures=in a Gaussian sense negatively curved).[0002]When commonly accepted and uniformly defined terms denominating well-known and especially recent shapes of shells and their parts hitherto were missing, imaginary or corporeal expressions are used within the text. They are highlighted by quotation marks, when they occur for the first time for their definition.[0003]Each shell's piece consists of individual “meshes”, that is, of small triangular, quadrangular or hexagonal units being arrayed without gaps. These units are bounded by linear load-bearing structural ele...

AI Technical Summary

Benefits of technology

"The present invention solves the problem of subdividing shells with unevenly spaced nodes into quad-meshes with coplanar node points at its corners. This is achieved by combining the flexibility of a triangle net of shell-pieces with the evenness of a quad net. The invention allows for the production of shells with free-formed and individually tailorable surfaces, without the need for cutting quad-meshes. The use of quad-meshes in large-scale structures is advantageous because it evenly distributes the load-bearing elements. The invention also allows for the production of cushion-roofs, cupolas, and other shell shapes that have a flat surface and are suitable for use as building envelopes or insulating panels. The selection and combination of shell-pieces can be modified during the planning process. The invention also allows for the production of opaque or not-transparent shells and can act as the second envelope of a conventional solid building."

Problems solved by technology

However, as a disadvantage, the lengths of bars and joints of shells being subdivided fairly evenly into triangular faces, including Geodesic cupolas (U.S. Pat. No. 2,682,235), all together are large in relation to the envelope's surface.

Besides, a lot of cutting waste arises during the production of the small triangular components.

During modeling of computer programs by means of splines or nurbs or by two arrays of curves crossing at right angles to each other within the surface, the rounding-off of ashlars including cambering the remained plane faces results into not-plane meshes and causes a large amount of data.

As a disadvantage, they are comparatively flat.

94): These shells are not feasible in a pure scale-trans subdivision, because the inverse curvature in the cross-section of an anticlastically bent-up boundary region of the predominantly synclastic shell would cause an inverse curvature in the curve of the border-arc of a bent-up boundary region being situated in the transverse direction.

It is not possible to achieve that straight lines, being aligned with these lines in plan, form an equilateral triangle or an equilateral or irregular polygon having more than four sides in plan.

Even a pure translational cupola having four enlargements in a symmetric shape already would have the problem that high openings would implicate very large zenith's heights.

But the border-arc 22 of the new additional opening 2 on the shell's left side is not useful because it joins too flatly to the ground.

Besides, the old opening consequently having been changed has a statically unfavorable section 23 of the border-arc.

Although the scaling in the left half of the shell is not regular, but an irregular, intuitive, and time-consuming stretching mesh by mesh, the degree of ductility has been too low to avoid this inverse curvature within the border-arc of the front opening.

Images